I agree, tournaments to start because of freerolls. You get lots of tourney practice at them, along with grinding up a starting BR. Besides, micro cash game rake can be insanely high on some sites. I guess if you have a good rakeback deal or loyalty program it might not be too bad though...
After that you have to choose between micro sngs or mtts to start. Sngs are much lower variance, but usually a bit less soft overall(which is a good thing since you can practice against fairly good players for cheap). Mtts can be huge variance depending on the number of entries and the particular format. I'd probably suggest grinding the smallest sngs until you can become profitable in them, because if you can beat sngs then you can surely beat mtts of the same stakes. Then start taking shots at mtts, while still grinding sngs to help keep the big mtt swings to a minimum. The practice at the sngs against the small-stakes regs there will really really really help your mtt game so much, especially late-game and at the FT where it really counts
In short, use freerolls and then micro sngs to grind up mtt/satellite entries and you will eventually hit a big score. Once you do, try not to move up stakes too quickly or take big shots though. Positive tilt can be just as devastating to your roll as normal tilt can.
Lastly, never view it as a career tbh. More like a profitable hobby or a part-time/seasonal job that you enjoy. Even when you do make enough to live on and such, you'll need something to invest your profits into anyway. And having another profitable hobby, a small business, or some kind of work is really improtant for the added stability and mainly just to avoid getting too burned out on the poker grind. Tons of successful poker regs have something like this.